Being associated with Calcutta University and studying are not the same thing. Calcutta University is associated with 147 colleges. It serves as a governing body for administration and exam administration. 

Heritage is merely an autonomous private institution that has recently been connected with Calcutta University. It has superior infrastructure and management to Charuchandra College. 

Charuchandra College, on the other hand, has a better faculty and also includes 26 faculty members for the Ph.D. program. However, it does have a long history of being affiliated with CU and has a better notable Alumni base

As for AJC bose college, it has a NAAC rating of C. Even lower. Its grade point is 1.83 whereas among the 3 colleges the highest grading is that of Charuchandra college -2.52. 

I would say go for government-aided institutions instead of private institutes. Rest is up to you.